Please find attached a project which demonstrates using custom themes for RadTextBox and RadLabel. You may not be able to observe the themes at design-time at first, but here is how you should workaround the issue:
With the Form's Design mode closed, open the code editor of the form.
Press F7 to open the Design mode.
Now you will be able to see the themes applied at design-time.
Generally, when you are making your own project with custom themes, you will not be able to observe the theme for RadTextBox at design-time at first. However, it will be correctly applied at runtime. To be able to see it applied in the design-time as well, close and reopen the Visual Studio with the corresponding solution.
If you have additional questions, feel free to contact me.
the Telerik team
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